Аннотация:Mountain lakes, especially those located at an altitude of 2000-3000 m above sea level, can be model objects for studying global climate changes, as their ecosystems are particularly sensitive to external impacts. The assessment of quantitative and qualitative changes in the hydrobiological communities of the high mountain lakes of Altai, in particular zooplankton, is important in predicting the development of lake ecosystems under different climate change scenarios. 19 lakes were studied in the Kara-Kudur, Saryachik and Chibit systems and Ukok Plateau in 2000 and 2017-2018. It was revealed that during this period in Altai there was a tendency towards air temperature increase in winter and transition seasons. There were structural changes of zooplankton community in the lakes of Kara-Kudur, Saryachik and Chibit systems. However, zooplankton is now dominated by species, which are indicators of organic matter accumulation in the upper layers of bottom sediments. In lakes of the Ukok Plateau during the past 20 years, there was also an increase in the number and biomass of zooplankton, the emergence of phytophilic and nectobenthic species, which may indicate an increase in trophic status of lakes.
